This study proposes to test the clinical effectiveness of a Computerized Decision Support System for Depression (CDSS-D) in improving treatment outcomes for patients with a major depressive disorder (MDD). The Texas Medication Algorithm Project (TMAP) MDD algorithm provides the framework for the clinical content in the CDSS-D. The algorithm is an evidence-based algorithm that was developed by an expert consensus panel that included national experts in depression, local physicians, consumers and advocates. The CDSS-D is designed to ensure a high degree of adherence to a well-developed pharmacological algorithm for the treatment of MDD in the public health sector. After the initial database and rules engine for the CDSS-D application were developed, reliability testing was conducted. The last phase of testing involved psychiatrists using the CDSS-D program in two public mental health clinics. The field study demonstrated feasibility and acceptability of the CDSS-D. The proposed study will entail implementation at three mental health facilities (Bluebonnet Trails Community MHMR Center, Parkland Memorial Hospital Outpatient Clinic, and Texas Panhandle MHMR Center) in order to assess the effectiveness of the CDSS-D system. Psychiatrists will be randomized either to the computerized algorithm (CDSS-D), the paper and pencil algorithm for the treatment of depression (PPA-D), or Usual Care for Depression (UC-D). Physicians randomized to an algorithm treatment group will attend an additional workshop on the implementation of treatment algorithms, and they will be trained in the use of either the computerized algorithm platform or the use of a paper-pencil version of the algorithm. A total of 540 participants will be enrolled into the study who have major depressive disorder and are either entering treatment or are requiring a change in their treatment. The patient outcomes in the CDSS-D, PPA-D, and UC-D will be evaluated in terms of clinical symptoms, function, and quality of life (aim 1) assessed by an evaluator, blind to treatment assignment, every 3 months for a total of 12 months. The primary aims of the study are to: 1) assess the of CDSS-D implementation in terms of patient outcomes (reduction of symptoms, changes in level of functioning, and quality of life measures); 2) conduct an assessment of cost and utilization of the CDSS-D in a the public mental health sector; 3) directly assess the extent that the CDSS-D influences physician behavior; and 4) To compare the difference in patient outcomes with the difference in cost in the CDSS-D. Comparisons will be made between CDSS-D, PPA-D, and UC-D. [unreadable] [unreadable]